The Prologue to The Future of Life is structured as a letter from American biologist E. O. Wilson to the 19th-century American writer and naturalist Henry Thoreau. Wilson begins by telling Thoreau he’s speaking to him from the site of Thoreau’s cabin, on Walden Pond, not simply because Wilson lives nearby, but because he’s trying to put himself in the best position possible to imagine how Thoreau would have responded.

Wilson goes on to say that the environment at Walden Pond facilitates this exercise, because it’s mostly unchanged since Thoreau lived there: “Its ambience can be expressed in similar language” (xii). Wilson notes that in terms of major scientific figures, he and Thoreau are also closely linked: Charles Darwin’s On the Origin of Species was published in Thoreau’s lifetime, and as a younger man, Wilson had tea with Charles Darwin’s last surviving granddaughter and discussed his research with a descendent of one of Darwin’s close friends.

However, Wilson observes significant changes since Thoreau’s day as well. The makeup of the forest has changed, with the American chestnut, which once composed a quarter of Eastern forests, having disappeared—wiped out by a European fungus—and species like red maple having become more abundant. Wilson imagines walking with Thoreau through these woods, with Thoreau—as a member of what Wilson describes as the tribe interested in big organisms—listening for animal calls and searching for scat, and Wilson, as a “lover of little things” (xv), turning over rotten logs in search of invertebrates.